Hydrodynamically supported vertical journal bearings have been used for ceiling fans before the turn of the century. The hydrodynamic radial suspension of the journal shaft was so effective in reducing wear, that some of the original fans, in nearly continuous operation, are still operating to this day!
The subject bearings are highly desirable for ceiling fan applications for a number of other reasons as well: they are essentially noiseless over the entire life of the fan, they have a substantially infinite life, and their energy efficiency is higher than that of comparable ball bearings.
In the original ceiling fans, the air flow was unidirectional only; recently it became desirable to reverse the air flow direction for energy efficient winter operation, or for low draft summer operation.
In the aforementioned state of the art vertical journal bearings, a helical groove on the journal is pumping the oil up in the vertical direction. If the shaft rotation were reversed, however, the oil would not be pumped up as required.
For this reason manually reversible pitch blades have been marketed for nonreversible rotors. These blades are, however, cumbersome to reverse in situ. A market survey indicated that this feature is the major reason for the "loss of sale" of the subject fan, since a number of comparably priced electrically reversible fans are being marketed, alas with greatly inferior bearings. It appears that the trend toward electrically reversible fans will accelerate.
The subject invention, accordingly, is directed but not limited toward ceiling fans with hydrodynamically suspended journal bearings, which bearings are capable of operating in both directions of rotation.